@Amir Portal  I think you should stay open to all areas. 

We had hoped to rent our house for short-term or mid-term stays.

But if they don’t even bother to fill out the forms to apply, or get a basic job to make ends meet, or borrow money from family or friends/ somebody else besides you, then they can’t stay.

We want to acquire a property in one of these areas, not only as an investment but also as a place where we can stay when we visit the United States.

I would also weigh if you plan on staying in the home you are in now for a long time or move in the next 5 years.

Are you looking to stay in the city? 

I personally would stay away from condo-tels as they will be even worse and you'll have less opportunity to cash flow. 

Without my wife's direct involvement, I think some of our homes would have struggled to stay afloat.   

So that has been my "next action step" to wait for a clog to happen again and have him camera it, but it has now been almost 1.5 years with no incidents.TLDR: There is a chance that the bottom bathroom tub/toilet could fill with sewage during a guest stay, but I am hopeful that the next time it happens will be the last.

I would suggest going to independent landlords and staying away from larger apartment complexes.